350
20 Dating the First Migration to New Zealand
The generation length of the two Moriori lines suggests a far lower life
expectancy than for tropical Polynesia. The main Rarotongan line has an average generation of 25.5 years, perhaps reflecting the difference in life expectancy
between those living in tropical Polynesia with its abundance of fruits and vegetables and a long horticultural tradition and those living as hunter/gatherers in the cold
harsh Chatham Islands.
20.3 Establishing a Generation Length for the Tamahiwaki Line
To establish a generation length for the Moriori lines entails finding at least two
independently derived chronological markers. One marker is available from the
date at which the lines were recorded in writing. The obvious occasion where
another might be available is the arrival in the Chatham Islands during the Medieval
Climatic Optimum of the Eastern Polynesian migration canoes, the Rangimata and
Rangihoua. Alexander Shand, who recorded the two long Moriori genealogies, provides the information that the builder of the Rangimata canoe was Ru of the Rauru
clan, whose wife Pe was a niece of Kahukura [3]. In the last chapter we established a secure date for Kahukura of AD 1230. Adding a generation to this gives a
date for the Rangimata of about 1255. With the transmission of the Tamahiwaki line
fixed at 1868 (adding two generations to its length because Tamahiwaki was a greatgrandfather in 1868) we have a span of 613 years and 27 generations. This provides
an initial estimate for a generation length of 22.7 years. The Maihoua genealogy
does not show the generation in which the Eastern Polynesian canoes arrived. We
can obtain a second estimate for the generation length of the Tamahiwaki line from
the arrival of Tu-te-rangi-marama.
In the last chapter we dated Tu-te-rangi-marama to 360 BC. Computing an average generation length for the Tamahiwaki line from Tu-te-rangi-marama in 360 BC
to 1868, a span of 2,227 years and 105 generations, gives a generation estimate of
21.21 years, versus the estimate of 22.7 over only 613 years. The confirmation of the
date for Tu-te-rangi-marama through the Lake Huguang Maar climate proxy gives
weight to this estimate made with a longer database.
20.4 Computing First Settlement Dates for the Chatham Islands
and for New Zealand
Using the Moriori Tamahiwaki generation length of 21.21 years, it is simple to estimate the time for the first settlement of the Chatham Islands. Rongomaiwhenua,
in whose time, Moriori tradition tells us, men first came to the Chathams, lived 21
generations before Tu-te-rangi-marama. With a generation length of 21.21 years this
gives a date for the first settlement of the Chatham Islands of 805 BC. Given the existence of an intense cold period at this time, it seems possible that the first settlement
of the Chatham Islands may either have been the result of an enforced migration
20 Dating the First Migration to New Zealand
The generation length of the two Moriori lines suggests a far lower life
expectancy than for tropical Polynesia. The main Rarotongan line has an average generation of 25.5 years, perhaps reflecting the difference in life expectancy
between those living in tropical Polynesia with its abundance of fruits and vegetables and a long horticultural tradition and those living as hunter/gatherers in the cold
harsh Chatham Islands.
20.3 Establishing a Generation Length for the Tamahiwaki Line
To establish a generation length for the Moriori lines entails finding at least two
independently derived chronological markers. One marker is available from the
date at which the lines were recorded in writing. The obvious occasion where
another might be available is the arrival in the Chatham Islands during the Medieval
Climatic Optimum of the Eastern Polynesian migration canoes, the Rangimata and
Rangihoua. Alexander Shand, who recorded the two long Moriori genealogies, provides the information that the builder of the Rangimata canoe was Ru of the Rauru
clan, whose wife Pe was a niece of Kahukura [3]. In the last chapter we established a secure date for Kahukura of AD 1230. Adding a generation to this gives a
date for the Rangimata of about 1255. With the transmission of the Tamahiwaki line
fixed at 1868 (adding two generations to its length because Tamahiwaki was a greatgrandfather in 1868) we have a span of 613 years and 27 generations. This provides
an initial estimate for a generation length of 22.7 years. The Maihoua genealogy
does not show the generation in which the Eastern Polynesian canoes arrived. We
can obtain a second estimate for the generation length of the Tamahiwaki line from
the arrival of Tu-te-rangi-marama.
In the last chapter we dated Tu-te-rangi-marama to 360 BC. Computing an average generation length for the Tamahiwaki line from Tu-te-rangi-marama in 360 BC
to 1868, a span of 2,227 years and 105 generations, gives a generation estimate of
21.21 years, versus the estimate of 22.7 over only 613 years. The confirmation of the
date for Tu-te-rangi-marama through the Lake Huguang Maar climate proxy gives
weight to this estimate made with a longer database.
20.4 Computing First Settlement Dates for the Chatham Islands
and for New Zealand
Using the Moriori Tamahiwaki generation length of 21.21 years, it is simple to estimate the time for the first settlement of the Chatham Islands. Rongomaiwhenua,
in whose time, Moriori tradition tells us, men first came to the Chathams, lived 21
generations before Tu-te-rangi-marama. With a generation length of 21.21 years this
gives a date for the first settlement of the Chatham Islands of 805 BC. Given the existence of an intense cold period at this time, it seems possible that the first settlement
of the Chatham Islands may either have been the result of an enforced migration